I have just been examining all the sketches I have used in making this
work. How many there are which fully satisfied me at the beginning, and
which seem feeble, inadequate, or ill-composed, now that the paintings
are advanced. I cannot tell myself often enough that it means an immense
deal of labour to bring a work to the highest pitch of impressiveness
of which it is capable. The oftener I revise it, the more it will gain
in expressiveness.... Though the touch disappear, though the fire of
execution be no longer the chief merit of the painting, there is no
doubt about this; and again how often does it happen that after this
intense labour, which has turned one's thought back on itself in every
direction, the hand obeys more swiftly and surely in giving the desired
lightness to the last touches.
_Delacroix._